Abstract: Power converter with a controllable first switch and a diode and a controllable second switch and a second diode, a transformer with a primary winding and a secondary winding, of which the secondary winding forms at least part of a control circuit for the first switch. As a result of an alternating voltage across the primary winding, a synchronously alternating voltage is induced in the secondary winding, which can be used to control the first switch essentially synchronously with the second switch.

Abstract: A push-pull type self-oscillating power converter uses a main power transformer connected to a current transformer in series in such a way that a secondary current flowing through secondary sides of the two transformers is feedback to the primary side of the current drive transformer to generate a drive current for driving two switches. The drive current is proportional to the secondary current in the secondary side of the main power transformer.

Abstract: Embodiments of determining power to be supplied to the load using an expected voltage decrease that would result from supplying power to the load are disclosed.

Abstract: A circuit for transmitting signals includes a transformer having an input side and an output side, the input side having a first end and a second end. A first transistor is coupled to the first end of the transformer, the first transistor being configured to provide a first signal to the first end in response to an input signal transitioning to a first state. A second transistor is coupled to the second end of the transformer; the second transistor being configured to provide a second signal to the second end in response to the input signal transitioning to a second state. The output side is configured to output differential signals according to the first and second signals applied to the transformer.

Abstract: A comparing circuit and a control loop are used to maintain the peak level of current flowing through an inductor of a flyback converter. An inductor switch control signal controls a switch through which the inductor current flows. The inductor current increases at a ramp-up rate during a ramp time and stops increasing at the end of the ramp time. The comparing circuit generates a timing signal that indicates a target time at which the inductor current would reach a predetermined current limit if the inductor current continued to increase at the ramp-up rate. The control loop then receives the timing signal and compares the target time to the end of the ramp time. The pulse width of the inductor switch control signal is increased when the target time occurs after the end of the ramp time. Adjusting the frequency and pulse width controls the peak of the inductor current.

Abstract: First and second semiconductor switches which are activated alternately are provided between ends of a primary winding and a common potential point, wherein a DC power supply voltage is supplied to a center tap. An electric current flowing into a load is fed back to thereby subject the semiconductor switches to PWM control. Series circuits consisting of capacitors and semiconductor switches are connected between the center tap of the primary winding and the ends of the same. The semiconductor switches are activated in synchronism with the first and second semiconductor switches, thereby preventing occurrence of an anomalous high voltage, which would otherwise be caused at the time of switching operation.

Abstract: A power converter includes a transformer having a primary winding and a secondary winding, and a plurality of switches coupled to the primary and secondary winding, the plurality of switches responsive to at least one control signal to short both the primary and secondary winding during a first reset time interval. An electronic device including such a power converter and related methods are also provided. A power converter having a plurality of DC to DC converters coupled in parallel is also provided.

Abstract: A direct-current converter includes a high-frequency converting circuit converting voltage of a direct-current power source to alternating-current voltage, a transformer having primary and secondary windings P, S and a rectification smoothing circuit rectifying and smoothing voltage induced in the secondary winding. This converting circuit includes other transformer having first and second windings n1, n2, switching element Q1 having a source connected to a negative pole of the power source and a drain connected to a positive pole thereof through winding n1, and switching element Q2 having a source connected to the negative pole of the power source and a drain connected to the positive pole thereof through winding n2, element Q2 being turned on/off alternately to element Q1 being turned on/off. Winding P is connected to a point between winding n1 and the drain of element Q1 and another point between winding n2 and the drain of element Q2.

Abstract: A DC power source voltage is supplied to a center tap of a primary winding, and first and second semiconductor switches alternately turned on are disposed between each of both ends of the primary winding and a common potential point, and a current flowing through a load is fed back and PWM control of each of the semiconductor switches is performed. Also, snubber circuits are respectively connected between a ground and the center tap of the primary winding, and an abnormal high voltage at the time of switching is reduced. Also, a parallel running of plural inverters is simply performed by disposing PWM comparators corresponding to the first and second semiconductor switches.

Abstract: In a double-ended isolated DC-DC converter, by using a main transformer and first and second pulse transformers, a first power switch of a primary side circuit and a first synchronous rectifier of a secondary side circuit are driven with complementary timing, and a second power switch of the primary side circuit and a second synchronous rectifier of the secondary side circuit are driven with complementary timing. A first turn-off edge signal and a first turn-on edge signal generated in a primary side control circuit are transmitted to the secondary side via the first pulse transformer so as to generate a driving signal of the first synchronous rectifier. In addition, a second turn-off edge signal and a second turn-on edge signal generated in a primary side circuit are transmitted to the secondary side via the second pulse transformer so as to generate a driving signal of the second synchronous rectifier.

Abstract: A DC/DC converter includes an input filter, a half-bridge converter without PWM (Pulse Width Modulation) control function, a synchronous rectifier, an output capacitor, and a DC transformer. The DC transformer includes a magnetic core, a primary winding, a first secondary winding, and a second secondary winding. The magnetic core of the DC transformer includes a first leg, a second leg having a first air gap, and a third leg having a second air gap. The first secondary winding is wound on the first leg and the second leg, and induces a first inductance by the first air gap. The second secondary winding is wound on the first leg and the third leg, and induces a second inductance by the second air gap.

Abstract: An on-vehicle power supply device is connected to a vehicle battery with revealing. The on-vehicle power supply device is used for receiving a DC input power supplied by the vehicle battery, and the on-vehicle power supply device induces a plurality of high-frequency voltages through a single isolation transformer at the same time, and then transforms the high-frequency voltages to produce at least one AC output voltage and DC output voltage. In addition, the on-vehicle power supply device further includes a rechargeable battery. The rechargeable battery can be charged when the DC input power is importing. When the DC input power stops importing, the rechargeable battery is used for supplying a backup power to the isolation transformer, and the rechargeable battery keeps producing AC output voltage and DC output voltage. Hence, the present invention can achieve the effects of multipurpose, safety, and continuity.

Abstract: In a two stage inverter providing power to a load, a first stage component is operable to receive a first voltage input and a first control input to generate a first voltage output, which is higher than the first voltage input. The first control input is indicative of the power provided to the load. The first voltage output varies in response to a change in the first voltage input by a predefined function. A second stage component of the inverter is operable to receive the first voltage output and a second control input to generate the power as an output. The second control input is indicative of the power provided to the load. A controller component of the inverter is operable to receive a feedback input indicative of the power required by the load and generates the first and second control inputs.

Abstract: Various embodiments of the present invention provide voltage converters and methods for using such. As one example, a voltage converter is disclosed that includes a transformer, an operational detector, and a controllable oscillator. The transformer includes a first winding and a second winding, and the operational detector provides an electrical output corresponding to an operational characteristic of the transformer. The controllable oscillator provides a clock output with a frequency corresponding to the electrical output. This clock output at least in part controls application of a voltage input to the first winding.

Abstract: The present invention provides a power supply suitable for a neon light, which power supply has a continuous output and a high power factor in excess of 0.9. The present invention does not require a front-end boost converter.

Abstract: A dual output programmable power supply is disclosed. The dual output programmable power supply includes an AC input train including an active power factor correction circuit, a half-bridge square wave driver coupled to the AC input train through a boot strap circuit, and a pair of primary side transistors coupled to a transformer, the primary side transistors being driven by the half-bridge square wave driver. Four transistors in a bridge configuration are coupled to a transformer secondary side and to a DC input, the four transistors being driven as a bridge of active synchronous rectifiers by a full-bridge gate driver in an AC mode of operation, and the four transistors being driven as a full-bridge square wave converter by the full-bridge gate driver in a DC mode of operation. A pair of DC/DC converters is coupled to an output of the four transistors in the bridge configuration, each DC/DC converter providing a regulated output.

Abstract: A switching regulator that practices the current invention includes a high-side switch M1 connected between an input voltage and a node Lx. A low-side switch is connected between the node Lx and ground. An inductor L is connected between Lx and an output node (VOUT). A filtering capacitor connects VOUT to ground. The switching regulator has two distinct operational phases. During the first operational phase, the high-side switch is OFF and the low-side switch is ON. During the second operational phase, the high-side switch is ON and the low-side switch acts as a current source. During transitions between the second and first operational phases, the low-side switch is controlled to momentarily decrease the regulated drain-to-source current.

Abstract: Described is an inverter device suitable for driving a cold cathode fluorescent lamp (CCFL), comprising a transformer having a primary winding and a secondary winding. The primary winding has two terminals connected to a return-path terminal of a direct current (DC) power source through a second switch and a third switch, respectively, and a center tap connected to an output of the DC power source through a first switch. A signal controlling unit is further included to control the switches in such a manner that the second and third switches are on concurrently or alternatively in cooperation with the first switch. As such, an alternating current (AC) power is fed to the primary winding of the transformer and an output of the transformer is supplied to the CCFL.

Abstract: A technique for suppressing lowering of withstand voltage and lowering of breakdown resistance and reducing a feedback capacitance of a power MISFET is provided. A lateral power MISFET that comprises a trench region whose insulating layer is formed shallower than an HV-Nwell layer is provided in the HV-Nwell layer (drift region) formed on a main surface of a semiconductor substrate in a direction from the main surface to the inside. The lateral power MISFET has an arrangement on a plane of the main surface including a source layer (source region) and a drain layer (drain region) arranged at opposite sides to each other across a gate electrode (first conducting layer), and a dummy gate electrode (second conducting layer) that is different from the gate electrode is arranged between the gate electrode and the drain layer.

Abstract: A DC power source voltage is supplied to a center tap of a primary winding, and first and second semiconductor switches alternately turned on are disposed between each of both ends of the primary winding and a common potential point, and a current flowing through a load is fed back and PWM control of each of the semiconductor switches is performed. Also, snubber circuits are respectively connected between a ground and the center tap of the primary winding, and an abnormal high voltage at the time of switching is reduced. Also, a parallel running of plural inverters is simply performed by disposing PWM comparators corresponding to the first and second semiconductor switches.

Abstract: A transforming circuit for power supplier includes a primary winding coil; a secondary winding coil and a secondary rectifier circuit, an AC power being transformed by the secondary winding coil in accordance with a winding turns ratio relative to the primary winding coil and converted by the secondary rectifier circuit into a first-potential DC power; N+1 sets of potential modifying circuits, connected in parallel with the first-potential DC power, each set of potential modifying circuits being based on the first-potential DC power and transformed thereof into N+1 sets of second-potential DC power at differential potential, N?1. Thereby, DC power at different potentials can be provides so that the power output can be more flexible and effective.

Abstract: A boost control module operates semiconductor switches of a boost converter circuit in an avalanche mode to precharge a boost output capacitor. The boost control module comprises a switching module that complementarily transitions a first semiconductor switch and a second semiconductor switch between ON and OFF states when a current does not exceed a maximum current threshold. The switching module transitions the first semiconductor switch and the second semiconductor switch to the OFF state when the current exceeds the maximum current threshold. The switching module maintains the first semiconductor switch and the second semiconductor switch in the OFF state until at least one of the inductor current is less than or equal to a minimum current threshold.

Abstract: A method for operating a push-pull converter in an above resonant frequency operating mode, where the above resonant frequency operating mode produces a switching frequency that is higher than the natural operating resonant frequency of the converter circuit. As a result, the resonant period is longer than the turn-on period of each of the switches in the primary circuit. The push-pull converter has two power switches operating in alternating sequence. The push pull converter also includes a transformer with a primary winding coupled to the power switches and a secondary winding coupled to a secondary circuit, and an output capacitor. The method also includes generating an operating resonant frequency from a leakage inductance of the transformer in series with a an input capacitance; and generating a switching frequency for the power switches that is higher than the operating resonant frequency.

Abstract: A voltage up and down synchronization and rectification type DC-DC converter goes up and down an input voltage using an inductor. The voltage up and down synchronization and rectification type DC-DC converter comprises a voltage up and down use rectification circuit including a pair of PMOS and NMOS transistors connected in parallel to each other.

Abstract: A full bridge inverter includes a push/pull control chip outputting a first control signal and a second control signal. Each duty cycle of the two control signals is smaller than 50%. Moreover, both a first driver and a second driver are coupled to the push/pull control chip and a DC power. A full bridge switch assembly with four N-MOSes couples to the DC power, the first driver, the second driver and a transformer, and converts the DC power into an AC power by the first driver and the second driver. The AC power is transmitted to a first side of the transformer.

Abstract: Enhancement of the power conversion efficiency and reduction of switching noise of a power supply circuit are achieved. The power supply circuit includes, on the primary side, a composite resonance type converter formed from a current resonance type converter and a partial voltage resonance circuit in combination, and is configured so as to produce a plurality of secondary side DC output voltages. A particular one of the plural secondary side DC output voltages is controlled to a constant voltage by variably controlling the switching frequency of a primary side switching converter. Each of the remaining secondary side DC output voltages is controlled to a constant voltage by adjusting the level of control current to be supplied to a controlling winding of a control transformer in response to the level of the secondary side DC output voltage to adjust the inductance of a controlling winding of the control transformer inserted in a rectification current path.

Abstract: A switching power supply circuit includes a plurality of switching converters, each including a partial resonance voltage circuit combined with a current resonance type switching converter using a half-bridge connection system. For changeover control, a rectification circuit serves as a voltage doubler rectification circuit at an AC voltage less than or equal to 150V, but serves as a full-wave rectification circuit at an AC voltage greater than or equal to 150V. The voltage output of the converters is fed back to a rectification current path by a power factor improving transformer, the rectification current being interrupted by means of a rectification diode to expand the conduction angle of the AC input current. A DC switch circuit in the rectification current path is switched between on and off conditions in response to the input of a predetermined starting signal to control the starting order of the secondary side DC output voltage.

Abstract: Provided is an inverter circuit including a rectification and filter circuit and an inverter driver circuit interconnected the rectification and filter circuit and a load. The inverter driver circuit comprises a second controller for receiving light adjustment cycle signals and outputting electrical conduction cycle signals wherein the second controller is either electrically connected to a power source or electrically connected to the rectification and filter circuit for obtaining a wave current, and an electrical conduction of the electrical conduction cycle signals depends on input on/off of the wave current at the second controller; and a driver operates in response to electrical conduction cycle signals and on/off of DC. A flashing effect is produced on the load and thus a power factor correction effect is produced without power factor corrector being involved.

Abstract: In a two stage inverter providing power to a load, a first stage component is operable to receive a first voltage input and a first control input to generate a first voltage output, which is higher than the first voltage input. The first control input is indicative of the power provided to the load. The first voltage output varies in response to a change in the first voltage input by a predefined function. A second stage component of the inverter is operable to receive the first voltage output and a second control input to generate the power as an output. The second control input is indicative of the power provided to the load. A controller component of the inverter is operable to receive a feedback input indicative of the power required by the load and generates the first and second control inputs.

Abstract: Apparatus, methods system and devices for using alternated duty cycle control to achieve soft-switching for at least one switch of the two half-bridge switches. When soft-switching can be only achieved for one switch, alternated duty cycle control alternates the soft-switching between the two switches so that each switch is soft-switched during half of the time and hard-switched during the other half, keeping equal power losses distribution between the switches. When alternated duty cycle control is used, any asymmetry in the duty cycle does not cause asymmetric components stresses or transformer DC bias.

Abstract: A DC converter alternately turns on and off a main switch Q1 connected in series with a primary winding P1 of a transformer T and a sub-switch Q2 contained in a series circuit connected to each end of the primary winding P1 of the transformer T or to each end of the main switch Q1, rectifies and smoothes a voltage of a secondary winding S1 of the transformer T, and provides a DC output. The DC converter includes a time difference detection circuit 13 to detect an interval between when the main switch Q1 reaches a minimum voltage after the sub-switch Q2 is turned off and when the main switch Q1 is turned on and a first delay circuit 14 to delay the ON timing of the main switch Q1 according to an output from the time difference detection circuit 13 so that the main switch Q1 is turned on at around the minimum voltage.

Abstract: A buck converter has a driver circuit with a drive transformer that provides complementary voltages to the buck converter switches. The drive transformer may have two secondary windings, with one winding for each converter switch. As one converter switch experiences a rising gate voltage, the other converter switch experiences a falling gate voltage. Since both converter switches are controlled by the same driver switches, the converter switch dead time is very small. Preferably, at least one converter switch has a voltage shift circuit connected to the gate electrode. Adjustment of the voltage shift magnitude will advance or delay the turn on and turn off times of the switch. Hence, the converter switch dead time can be precisely adjusted by varying the voltage shift magnitude. Preferably, the converter switch dead time is less than 1 or 2 nanoseconds.

Abstract: The present invention relates to a semiconductor device that is employed in a switching power supply for which a higher output is required, prevents noise from the coil, transformer, and so forth and implements a high efficiency power supply. By connecting a current mirror circuit including a p-type MOSFET, an overcurrent detection level tuning circuit, an overcurrent detection circuit, and an intermittent oscillation control circuit to an FB terminal peripheral circuit that is a feedback signal input terminal, PWM control capable of varying the IDRAIN peak value is implemented for the transition from a heavy load state to a light load state and intermittent oscillation control is implemented for the transition between a light load state to a loadless state, such that noise from the coil, transformer, and the like is suppressed and higher efficiency is realized.

Abstract: A switching power conversion circuit comprises a saturable load assembly, a first switching inductance coil assembly and a second switching inductance coil assembly. The saturable load assembly is composed of a load and a saturable reactor. The first switching inductance coil assembly is connected to the saturable load assembly and a first potential. The second switching inductance coil assembly is magnetically coupled with the first switching inductance coil assembly, and is connected to the first switching inductance coil assembly and a second potential. When the first and second switching inductance coil assemblies are power switched, the saturation effect of the saturable reactor is exploited to let the terminal potential of the saturable reactor drop before switching, hence letting the terminal potential of the transfer switch be zero.

Abstract: A coaxial push pull transformer is an improved matrix transformer. A number of magnetic cores each contain a pre-wired secondary circuit. The secondary windings are tubular and extend through the core, and the ends of the tubular secondary windings are terminated to make connections to a secondary circuit, such as rectifiers. The cores are placed end to end with the tubular secondary windings aligned and the primary winding is then threaded through all of the cores, so that it is coaxial with the secondary windings when installed, for very low leakage inductance. In the design of the coaxial push pull transformer, care is taken to arrange the terminations of the transformer such that each termination is paired with another termination having a counter-flowing current, to cancel part of the field caused by the flowing currents so as to reduce the overall inductance of the terminals and interconnections.

Abstract: An over-power protection apparatus for self-excited power converter comprises a soft-start unit, an adjusting unit and a timing unit. A PWM unit of the self-excited power converter generates a switching signal in response to a compensating signal of the soft-start unit to control the output power of the self-excited power converter. The soft-start unit couples to the adjusting unit. The adjusting unit drives the soft-start unit and the PWM unit for modulating the switching signal to reduce the pulse width of the switching signal and the output power of the self-excited power converter once the short-circuit and over-load are happened at the output of the self-excited power converter. In the meantime, a timing unit starts to count. The timing unit drives the self-excited power converter to stop supplying the power source after the counting and the over-power lasting for a period of time.

Abstract: A soft-start circuit for a power converter including a switch controlled to cause the soft-start interval for the converter to be terminated when a predetermined condition is fulfilled. The predetermined condition is preferably the output voltage of the converter stabilizing at its normal operational level. The soft-start circuit detects when the predetermined condition is fulfilled and enables the converter to more rapidly recover after the initiation of a soft-start. In a preferred embodiment, the soft-start circuit includes a protection circuit for adjusting the soft-start voltage linearly as a function of the duration and magnitude of an overcurrent condition at the output so as to provide a scaled level of protection for the converter.

Abstract: First and second semiconductor switches which are activated alternately are provided between ends of a primary winding and a common potential point, wherein a DC power supply voltage is supplied to a center tap. An electric current flowing into a load is fed back to thereby subject the semiconductor switches to PWM control. Series circuits consisting of capacitors and semiconductor switches are connected between the center tap of the primary winding and the ends of the same. The semiconductor switches are activated in synchronism with the first and second semiconductor switches, thereby preventing occurrence of an anomalous high voltage, which would otherwise be caused at the time of switching operation.

Abstract: An inverter power supply system includes a half-bridge inverter circuit which includes a first switching element, a second switching element, a first auxiliary capacitor and a second auxiliary capacitor for converting a DC voltage from a DC power supply circuit to an AC voltage. An output control circuit outputs a first output control signal and a second output control signal with a phase difference of a half cycle to control the inverter circuit. An inverter driving circuit turns on the first (or second) switching element when the first (or second) output control signal turns ON while turning off the first (or second) switching element upon lapse of a first (or second) delay time for allowing the first (or second) auxiliary capacitor to discharge to a predetermined level after the first (or second) output control signal turns OFF.

Abstract: A single stage AC/DC converter with piezo transformer is provided. The AC/DC converter is suitable for converting an AC power into a DC power and is comprised of a rectification module, a switching module, a driving module, a piezo transformer, and an output rectification module. The present invention provides a new AC/DC converter with piezo transformer by combining the bulk circuit and the half-bridge circuit together.

Abstract: A synchronous rectifier circuit, comprising a power transformer which has a primary side, including first and second primary winding sections, and a secondary side, including first and second secondary winding sections, a rectifier circuit at the secondary side of the power transformer, which rectifier circuit comprises first and second MOSFETs associated with the first and second secondary winding sections, respectively, first and second current transforming means associated with the first and second secondary winding sections, respectively, and first and second drive circuits for the first and second MOSFETs, respectively, each current transforming means generating first and second currents which are dependent on the current of the associated secondary winding section of the power transformer, and each drive circuit comprising first and second branches to receive the first and second currents, respectively, generated by the current transforming means, and the first branch comprising a diode and a transcondu

Abstract: A synchronous DC-DC regulator, adapted to receive a high side pulsed signal and a low side pulsed signal that is substantially the inverse of the high side pulsed signal. The regulator includes an inductor, and a capacitor having one port connected to ground, and having a second port providing an output voltage of the DC-DC regulator. A driver is provided for driving pulses of current to the inductor when the high side pulsed signal is asserted. An undercurrent sense circuit is adapted to sense a driving current flowing through the driver and to assert a disable signal when the driving current is less than a predetermined amount. An enable/disable circuit is adapted to allow the low side pulsed signal to turn the switch on when the disable signal is not asserted, and to not allow the low side pulsed signals from turning the switch on when the disable signal is asserted.

Abstract: An electrical power converter receives input power of one type or level at input terminals and supplies output power of another type or level at output terminals. The power converter includes a high frequency transformer, an input circuit connected between the input terminals and the primary of the transformer, and an output circuit connected between the secondary of the transformer and the output terminals, a controller for controlling pulse width of current pulses produced by the input circuit, and a current limiting circuit. The current limiting circuit allows very high surge currents immediately upon demand without waiting for a voltage drop feedback circuit, then dynamically reduces the current limit over time based on the averaged current in the input circuit.

Abstract: An inductive device comprises an electric winding component having a generally toroidal shape, and a plurality of discrete magnetic components at least partially embracing the electric winding component so as to complete a magnetic flux path and to form at least one gap between end portions of the plurality of discrete magnetic components.

Abstract: A first charge/discharge element is connected in parallel to a coil porion of the primary coil of a converter transformer. A second charge/discharge element is connected in parallel to a coil portion of the primary coil. The first charge/discharge element is charged with the energy stored in the primary coil when the first switching element turns off. A smoothing capacitor is charged with the charge energy when the second switching element turns off. The second charge/discharge element is charged with the energy stored in the primary coil when the second switching element turns off. The smoothing capacitor is charged with the charge energy when the first switching element turns off.

Abstract: A driver circuit for driving a switching circuit driving a load, e.g., a gas discharge lamp, the drive circuit comprising an input trigger circuit receiving a pulsed input signal for controlling the generation of two drive signals, a first drive signal driving a high side switch of a half bridge switching circuit and a second drive signal driving a low side switch of the half bridge switching circuit, a circuit for providing a dead time between the first and second drive signals whereby both the first and second drive signals are substantially zero, the input trigger circuit generating a control signal for controlling the generation of the first and second drive signals based on a characteristic of the pulsed input signal and first and second drive circuits for providing the first and second drive signals.

Abstract: Chopper-type direct-current converter comprising a magnetic core (M), which comprises a first and a second side leg (MS1, MS2), the ends of which are connected to each other with pieces, and a center leg provided with an air gap and connected to the end pieces between the first and the second side legs. According to the invention, the secondary side filter coil is wound around the center leg. The primary and secondary windings are wound around the side legs so that the magnetic flux produced by them flows in the same direction as the magnetic flux of the filter coil.

Abstract: The present invention relates to a power supply arrangement for supplying power to a plurality of back and/or edge illumination devices (5) in a liquid crystal display unit (1), comprising a mains connection (7), a power converter (6) and at least one inverter (8). The power converter (6) is arranged to convert an AC voltage input to a DC voltage output, and the inverter (8) is connected to said DC voltage output, and arranged to convert said output to a voltage level adequate for driving said illumination devices (5). Furthermore, the inverter (8) is provided with mains isolation.

Abstract: It is aimed at decreasing losses not only in a synchronous rectifier circuit provided at a secondary side of a DC-DC converter, but also in a full-bridge switching circuit provided at a primary side thereof. The DC-DC converter comprises a transformer for voltage conversion, a synchronous rectifier circuit at the secondary side, and a full-bridge switching circuit at the primary side. The DC-DC converter performs synchronous rectifier control which uses switch transistors to change paths of currents flowing through the secondary coil in synchronization with switching operations at the primary side. The DC-DC converter detects currents flowing through a load at the secondary side, primary-side currents varying with the load currents, or primary-side input voltages to dynamically control off-timings of a synchronous rectification transistor at the secondary side.

Abstract: A modified push-pull booster circuit is proposed, wherein two alternately switching transistors are disposed on the primary winding of a transformer, and a bridge rectifier and a charging circuit are disposed on the secondary winding; wherein the bridge rectifier has a pair of inductors with inductive coupling installed on the first half and second half of the circuit. The push-pull circuit uses series inductance to step up the bus voltage, and, because of the degaussing effect when current is induced on the inductors, the inductance of the inductor can be decreased even without using snubber circuit, thus decreasing the peak voltage of the bridge rectifier, and balancing the magnitude of current flow in the secondary winding. By reducing the turn ratio on the transformer windings, the operating efficiency of the booster circuit can be considerably improved.